The questions are different. Obviously they'd be less crazy without Breitbart and Infowars. As far as only getting their news from Fox, I really don't know. Depends on what percentage of Republicans read Breitbart/Infowars vs ones who supplement Fox with MSM sources, even if they're still generally conservative (like The Wall Street Journal or even The National Review or something). The second group would probably become more crazy if they only watched Fox.
Would they be less crazy watching Fox News only; without Breitbart, Infowars, WSJ, or National Review?